initial commit of poker game

shared/token.js

@@ -0,0 +1,42 @@
+var crypto = require('crypto');
+
+/**
+ * Create token by uid. Encrypt uid and timestamp to get a token.
+ * 
+ * @param  {String} uid user id
+ * @param  {String|Number} timestamp
+ * @param  {String} pwd encrypt password
+ * @return {String}     token string
+ */
+module.exports.create = function(uid, timestamp, pwd){
+	var msg = uid + '|' + timestamp;
+	var cipher = crypto.createCipher('aes256', pwd);
+	var enc = cipher.update(msg, 'utf8', 'hex');
+	enc += cipher.final('hex');
+	return enc;
+};
+
+/**
+ * Parse token to validate it and get the uid and timestamp.
+ * 
+ * @param  {String} token token string
+ * @param  {String} pwd   decrypt password
+ * @return {Object}  uid and timestamp that exported from token. null for illegal token.     
+ */
+module.exports.parse = function(token, pwd){
+	var decipher = crypto.createDecipher('aes256', pwd);
+	var dec;
+	try{
+		dec = decipher.update(token, 'hex', 'utf8');
+		dec += decipher.final('utf8');
+	} catch(err){
+		console.error('[token] fail to decrypt token. %j', token);
+		return null;
+	}
+	var ts = dec.split('|');
+	if(ts.length !== 2){
+		// illegal token
+		return null;
+	}
+	return {uid: ts[0], timestamp: Number(ts[1])};
+};